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184

PRACTICAL ORGANIC CHEMISTRY

in a large round flask (i litre), and the contents of the flask
well shaken. On the addition of the phenol, the liquid immedi-
ately changes to a deep brown or black colour, and a heavy
dark-br-own oil separates out. When the phenol has been
added, the mixture is allowed to stand for 12 hours. The oil
has by that time collected at the bottom of the vessel, and may
be freed from acid by repeatedly decanting and pouring" in
fresh water (three or four times). The contents of the flask
consist of nearly equal quantities of para- and ortho-nitrophenol
mixed with resinous products. In order to separate the two
isomers, the product is distilled in a current of steam (sec Fitf.
68, p. 107) until the distillate is almost colourless. The ortho-
compound distils in the form of a yellow oil, which may solidify
in the condenser, in which event the water is temporarily run
out of the condenser. The solid in the receiver is separated by
filtration and dissolved in spirit at 40, to which water is then
added, drop by drop, until a turbidity is produced. Yield, i 5
grams. The solid residue contains the para-compound mixed
with black, resinous substances, from which it is separated by
repeatedly extracting with boiling water. The united portions
of the aqueous extract are boiled with animal charcoal for
half an hour in a large basin, and filtered through a fluted filler
moistened with water. The filtrate is made alkaline with
caustic soda solution, and concentrated to a small bulk (roo
c.c.). If tarry matter separates, it must be filtered through a wet
filter. To obtain the free para-compound, the concentrated
aqueous solution of the sodium salt is cooled, and the separated
sodium salt filtered. The crystals arc dissolved and acidified
with concentrated hydrochloric acid, and the nitrophenol, whirh
separates, is filtered and recrystallised from hot water. Yield,
lo grams.

Properties,Q-NUrophcnol, sulphur-yellow needles, pos-
sessing a peculiar smell ; m. p. 45; b. p. 214" ; clistillable with
steam ; soluble in alcohol, ether, and hot water ; less soluble in
cold water.
^-Nitrophenol, colourless needles ; m. p. 114 ; easily soluble
in alcohol and hot water ; slightly soluble in cold water. See
Appendixi p. 295.